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Biomedical subjects

M Hayami

Publications and source records attributed to M Hayami.

At least 181 records · Page 10Linked to original sources
PubMed1986

Experimental inoculation of monkeys with autologous lymphoid cell lines immortalized by and producing human T-cell leukemia virus type-I.

Cynomolgus monkeys and squirrel monkeys were inoculated with autologous lymphoid cell lines immortalized by and producing human T-cell leukemia virus type-I (HTLV-I) in order to serve as an animal model of adult T-cell leukemia (ATL). The autologous cell lines were established from peripheral blood mononuclear cells (PBMC) from each monkey by co-cultivation with lethally irradiated MT-2 cells producing HTLV-I. All of these cell lines, which had monkey karyotypes, grew continuously without addition of interleukin-2 (IL-2) and expressed virus-specific proteins of HTLV-I and IL-2 receptor. After inoculation with the autologous cell lines, specific antibodies against HTLV-I proteins could be detected in their plasma, and transformed HTLV-I-infected cells could be recovered from their peripheral blood for at least 6 months. However, no signs of ATL have been observed to data, i.e. 2 years after inoculation.

Animals↗
PubMed1986

Structural analysis of p19 and p24 core polypeptides of primate lymphotropic retroviruses (PLRV).

Core polypeptides of primate lymphotropic retroviruses (PLRV) have very similar molecular weights. To discriminate between individual PLRVs we have compared two-dimensional tryptic peptide maps of 125I-labeled core polypeptides p19 and p24 of 11 isolates originating from humans and six simian species. Peptide maps showed homologies between all the simian viruses and the human isolates, but they were completely different from those of human T-cell leukemia virus type III (HTLV-III). In general p24s are more conserved than p19s. According to the relationship of their peptide maps we have classified the PLRVs into three groups, the human and chimpanzee isolates, macaque viruses, and green monkey virus.

Animals↗
PubMed1986

Detection of the X gene product of simian T-cell leukemia virus.

The gene product of the X region was examined in simian lymphoid cell lines producing simian T-cell leukemia virus (STLV), which is closely related to human T-cell leukemia virus (HTLV). By use of specific antibodies against pX peptides of HTLV-I, a protein of 41 kDa was identified as a pX product of STLV.

Animals↗
PubMed1986

A field study of infection with human T-cell leukemia virus among African primates.

African non-human primates were surveyed seroepidemiologically for natural infection of human T-cell leukemia virus type I (ATLV/HTLV-I) or its closely related virus(es). Materials from three genera (Cercopithecus, Papio, and Theropithecus), four species (grivet monkey, Anubis baboon, Hamadryas baboon, and gelada), totalling 983 animals under natural conditions, were obtained in a field study in Ethiopia. Virus infection was determined by the indirect immunofluorescence test using HTLV-I specific antigens. Animals seropositive for HTLV-I were found among grivet monkeys and Anubis baboons including the hybrid offspring between Anubis and Hamadryas baboons but not pure-Hamadryas baboons and geladas. From these results, the HTLV-I family was proved to be widespread on the African continent and was regarded as a common retrovirus among catarrhines.

Animals↗
PubMed1986

Hematologic abnormalities similar to the preleukemic state of adult T-cell leukemia in African green monkeys naturally infected with simian T-cell leukemia virus.

Studies were made of the hematologic features of 23 adult African green monkeys (Cercopithecus aethiops) naturally infected with simian T-cell leukemia virus (STLV), which is closely related to human T-cell leukemia virus type I. None of the STLV-infected monkeys showed any clinical signs, but their absolute lymphocyte count and percentage of atypical lymphocytes were significantly higher than those of uninfected monkeys. Three STLV-infected monkeys had especially high percentages of atypical lymphocytes. Most of the atypical lymphocytes were small- or medium-sized lymphocytes with a lobulate or convoluted nucleus, and were very similar to the leukemic cells in human cases of adult T-cell leukemia (ATL), while other atypical cells were large lymphoblastoid cells. Both types of atypical cells were positive for Leu2a and Tac antigens, and expressed STLV antigen after short-term culture. These findings suggested the presence of a preleukemic state in these STLV-infected monkeys similar to that seen in human ATL, and indicated the value of this natural infection system as an animal model of ATL in humans.

Animals↗
PubMed1986

Conventional and immunocolloidal gold electron microscopy of eight simian retroviruses closely related to human T-cell leukemia virus type I.

Simian retroviruses closely related to human T-cell leukemia virus type I (HTLV-I) were isolated from 8 species, examined by both conventional and thin section immunocolloidal gold electron microscopy, and compared with HTLV-I. Mature forms of simian viruses were found in extracellular aggregates and within cytoplasmic vacuoles. They were morphologically similar to each other and to HTLV-I. They consisted of a seemingly smooth envelope and a centrally located nucleoid. Their size varied considerably among species and also within the same species; this is characteristic of this group of retroviruses. No budding particles of simian viruses were observed. Thin section immunocolloidal gold electron microscopy using various human and simian sera showed that simian viruses were antigenically related to each other and to HTLV-I. One drawback of this otherwise very useful technique was the difficulty in identifying virions because of the poor preservation of their fine structure by fixation with glutaraldehyde alone. This was overcome by using materials prepared for conventional electron microscopy, in which virions showed weak but specific reactions with gold particles after deosmification and antigen restoration with sodium metaperiodate.

Animals↗
PubMed1985

Sequence homology of the simian retrovirus genome with human T-cell leukemia virus type I.

A retrovirus highly related to human T-cell leukemia virus type I (HTLV-I) was isolated from a T-cell line established from a seropositive pig-tailed monkey and the provirus genome was molecularly cloned using HTLV-I as a probe. The monkey virus (STLV) had the genomic structure of the LTR-gag-pol-env-pX-LTR. Analysis of the env-pX-LTR region revealed the 90% homology of the nucleotide sequence with that of HTLV-I in each region. This high homology of the sequence indicates that STLV is a member of the HTLV family, but apparently different from HTLV-I. This suggests that the possibility of recent interspecies transmission from monkeys to humans in the endemic area is very small. From its similarity to HTLV, STLV should be useful as an animal model in studies on natural HTLV infection and leukemogenesis of HTLV in humans.

Animals↗
PubMed1985

Isolation of simian retroviruses closely related to human T-cell leukemia virus by establishment of lymphoid cell lines from various non-human primates.

Simian retroviruses closely related to human T-cell leukemia virus (HTLV) were isolated by establishing virus-producing lymphoid cell lines from 7 species of non-human primates. By co-cultivation with human umbilical cord-blood cells and/or in the presence of interleukin-2, lymphoid cell lines were successfully established from the chimpanzee. African green monkey, pig-tailed macaque, red-faced macaque, Formosan monkey, Japanese monkey and bonnet monkey that had antibodies against HTLV antigens. These cell lines reacted with human sera of ATL patients and monoclonal antibodies against p19 and p24 of HTLV antigens. Cellular DNAs contained the provirus sequences homologous to HTLV-I by Southern blot hybridization. Moreover, they produced extracellular type-C virus particles and RNA-dependent DNA polymerase. All of these lymphoid line cells had Tac antigen, interleukin-2 receptor, and those of chimpanzee and red-faced macaque had helper/induced T-cell markers, while those derived from African green monkey had suppressor/cytotoxic T-cell markers. Furthermore, simian HTLV-related viruses of pig-tailed macaque, red-faced macaque and Japanese monkey were transmitted to human lymphocytes on co-cultivation.

Animals↗
PubMed1985

A field study of infection with human T-cell leukemia virus among asian primates.

Asian nonhuman primates were surveyed seroepidemiologically for natural infection with human T-cell leukemia virus (ATLV/HTLV) or a closely related agent. Materials from various primates (three genera [Macaca, Presbytis, and Hylobates], 17 species, totalling 1,079 animals) under natural conditions were obtained in the field study. Virus infection was determined by the indirect immunofluorescence test using HTLV-specific antigens. Animals seropositive for HTLV were found only among macaques originating from various localities, toque monkeys in Sri Lanka (17.5%), crab-eating macaques in Thailand (1.3%), stumptailed macaques in Thailand (1.5%), rhesus monkeys in Thailand (3.3%), and Celebes macaques in Indonesia (16.9%). Langurs and gibbons were seronegative. Thus the wide distribution of HTLV in nature among various macaques suggests that the introduction of this virus into primates occurred in ancient times.

Animals↗
PubMed1985

Distinct reactivities of four monoclonal antibodies with human interleukin 2 receptor.

Two new murine monoclonal IgG1 antibodies, H-31 and H-A26, were characterized in comparison with two previously obtained monoclonal antibodies against human interleukin 2 (IL-2) receptor (IL-2 R), anti-Tac and HIEI. In immunofluorescence assays with various human hematopoietic cells, H-31 and H-A26 antibodies both reacted with only IL-2 R-positive cells, and they precipitated IL-2 R molecules, glycoproteins with molecular weights of 60K and 53K daltons (gp60/gp53), from human T-cell leukemia virus type I (HTLV-I)-carrying MT-2 cells, as demonstrated by sequential immunoprecipitation after absorption of IL-2 R with anti-Tac. Antibody-binding competition assays showed that H-31 and anti-Tac, and H-A26 and HIEI, respectively, competed reciprocally in binding to the cells, and that anti-Tac also inhibited the binding of HIEI but not vice versa. H-31, like anti-Tac, strongly inhibited the IL-2-dependent proliferation of normal activated T-cells, absorption of IL-2 and direct binding of IL-2 to the cells, while H-A26, like HIEI, inhibited those processes only weakly. The spectra of reactivities of these antibodies with various simian cell lines derived by HTLV-I infection were different, as revealed by immunofluorescence studies. Human IL-2 R was shown to express a unique antigenic determinant, detected with HIEI, that was not detectable in IL-2 R molecules of Old and New World monkeys, and also to express determinants common to simian IL-2 R molecules. These observations indicate that H-31 and H-A26 recognize human IL-2 R molecules and that the antigenic sites on the IL-2 R molecule defined by H-31, H-A26, anti-Tac, and HIEI are different.

Animals↗
PubMed1985

Adult T-cell leukemia-like disease in monkey naturally infected with simian retrovirus related to human T-cell leukemia virus type I.

Spontaneous T-cell leukemia similar to human adult T-cell leukemia (ATL) was found in an African green monkey naturally infected with simian retrovirus closely related to human T-cell leukemia virus type I (HTLV-I). Monoclonal integration of the simian retrovirus was detected in the primary leukemic cells, suggesting an association of the retrovirus with ATL-like leukemia in the monkey.

Animals↗